Posts Tagged ‘transfer switches’

How to Select an Automatic Transfer Switch (ATS)

January 5th, 2016 | 5 Comments | Posted in Panel Building
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megaphone1To begin year 2016, we’re glad to publish this article by a new member from Kenya, specialized in electrical installations, maintenance and repairs.

He told us about his experience (20 years!) and he kindly sent us this article about automatic transfer switches. We tought it was interesting and decided to post it on the blog.

Remember you too can send us material and be published in the Electical Engineering Community blog! Just send us a mail.

For now, let’s enjoy this article…

The automatic transfer switches are used to automatically transfer the load from the utility power to a secondary or backup power source whenever power goes out, or as required.

A careful selection of the switch ensures adequate capability, safety, and maximum reliability under both normal and emergency conditions. As such, one must consider technical factors such as the size, type of load, continuous current rating, voltage rating and style. In addition, the price, compatibility and reliability must be considered.

Need for multiple transfer switches for emergency and standby power generation systems

June 8th, 2015 | 4 Comments | Posted in Electrical Safety
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Hi everybody, today let’s discover this article about power supply for emergencies and standby power generation systems. It was nicely sent by an active reader of the blog.

multiple transfer switches for emergency and standby power generation systems 1Automatic multiple transfer switches are widely used in most emergency and standby power generating systems, because of their reliability.
Some of these automatic multiple transfer switches also support over current protection and are designed as per the guidelines stated in NEC, which are deemed as yardsticks, as far as measuring the standards within the electrical industry is concerned.

These transfer switches are held mechanically, and are operated electrically, directly from the power source. They are known to transfer the load to the electrical equipment with greater reliability and accuracy when compared to the conventional switches. These switches are normally placed at the mains or at the secondary bus distribution terminal, and are responsible to feed the load to various branch circuits.

Factors to Consider while Buying Transfer Switches

October 25th, 2013 | Make a comment | Posted in Panel Building
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Check the last part of Nasir’s tutorial on Transfer Switches. If you want to send us your works, testimonies, observations, debates, tutorials or any other article you’ve wrote, please send us a mail.


A Transfer switch is used when two or more power sources are involved in the switching process.

There are two options present in the switching. One is the manual switching and the other one is the automatic switching.

Similarly, when buying a Transfer switch, you get the same two options, because depending upon the type of switching; there are two basic types of transfer switches :

  1. Manual Transfer Switch
  2. Automatic Transfer Switch


Three Way Transfer Switch

October 22nd, 2013 | Make a comment | Posted in Panel Building
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Last but one part of Nasir’s tutorial on Transfer Switches. Enjoy!


A Three way transfer switch is used for safe and reliable operation characteristics. Their main function is also the same as many other transfer switches, that is, to provide a continuous and uninterrupted flow of power to the load without producing any damage or fault in the system.

Usually when a transfer switch is used, it acts as a bridge between two power sources. One source is regarded as the “Preferred Source” and the other one is regarded as the “Alternate Source”.

The switch switches its contacts between these two sources, depending upon the availability of power in the preferred source, as the power availability in each of the sources is continuously monitored.

When it senses a power break in its preferred or primary sources, it switches its contacts to the alternate or backup energy source. This was the simple mechanism of a Transfer Switch.

Construction of a three Way transfer switch

But in case of a three way Transfer Switch, we get an additional power source, so that in case both the two sources break up due to some unfortunate reasons, we can still have an uninterrupted supply of power, due to the third redundant source.

So in short we can conclude that the construction of a three way transfer switch is almost more or less similar to a simple two way switch, just with the increment of a third source.

So where a two source switch is designed to survive a single load failure, a three way switch is more efficient and reliable since it survives even two load failures. Although it seems that it is a rare event, but still the probabilities show that its occurrence is not that less common.

This thing can be shown as follows:

Three way Transfer Switch 1


Static Transfer Switch

October 14th, 2013 | 1 Comment | Posted in Panel Building
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“Transfer switches: their types and usage”, this is how we could call Nasir’s series of tutorial for the Electrical engineering blog.

Here’s the 8th part (already!) about Static Transfer Switch.

Static transfer switches (STS) are such electrical devices which are used for very fast switching between electrical power sources.

They perform instantaneous switching operations and thus supply immediate power to the load.

Working of a Static Transfer Switch

This happens in such a way, that when one of the power supplying elements fail to supply power to the load, they promptly switch towards the backup power source, so that large or over sensitive loads do not have to face any interruption in the power supply.

For this rapid switching operation, they static transfer switches use semi-conductor elements such as SCR’s i.e. silicon controlled rectifiers to perform the shifting of load between two power sources.


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